Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int n, m;
int a[111][111], t[111][111];
int r[111], c[111];
vector<int> tmp, ans;
inline void check(int x) {
  tmp.clear();
  for (int i = 1; i <= 100; i++) r[i] = c[i] = 0;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      t[i][j] = a[i][j];
    }
  }
  for (int i = 1; i <= x; i++) {
    tmp.push_back(-1);
    r[1]++;
  }
  for (int i = 1; i <= m; i++) {
    for (int j = x + 1; j <= a[1][i]; j++) {
      tmp.push_back(i);
      c[i]++;
    }
  }
  for (int i = 2; i <= n; i++) {
    for (int j = c[1] + 1; j <= a[i][1]; j++) {
      tmp.push_back(-i);
      r[i]++;
    }
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      if (a[i][j] != r[i] + c[j]) return;
    }
  }
  if (ans.size() == 0 || ans.size() > tmp.size()) ans = tmp;
}
char str[2][5] = {"row", "col"};
int main() {
  scanf("%d%d", &n, &m);
  bool fl = true;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      scanf("%d", &a[i][j]);
      if (a[i][j] != 0) fl = false;
    }
  }
  if (fl) {
    return printf("0\n"), 0;
  }
  int minn = 233333333;
  for (int i = 1; i <= m; i++) minn = min(minn, a[1][i]);
  for (int i = 0; i <= minn; i++) {
    check(i);
  }
  if (!ans.size())
    printf("-1\n");
  else {
    printf("%d\n", int(ans.size()));
    for (auto x : ans) printf("%s %d\n", str[x > 0], x > 0 ? x : -x);
  }
  return 0;
}